public static void Main()
Console.WriteLine(DoMagic("KFV/209/09/24", 12));
public static string DoMagic(string number, int length)
string newNumberWithoutLetters = "";
string newNumberWithoutSings = "";
string newCutNumber = "";
if (number.Length > length)
char[] documentNumber = new char[number.Length];
documentNumber = number.ToCharArray();
if (!((documentNumber[i - 1] >= 65 && documentNumber[i - 1] <= 90) || (documentNumber[i - 1] >= 97 && documentNumber[i - 1] <= 122)) && cut)
newNumberWithoutLetters = documentNumber[i - 1] + newNumberWithoutLetters;
newNumberWithoutLetters = documentNumber[i - 1] + newNumberWithoutLetters;
if (howMuchCut == number.Length - length)
newNumber = newNumberWithoutLetters;
if (newNumberWithoutLetters.Length > length)
char[] documentNumber2 = new char[newNumberWithoutLetters.Length];
documentNumber2 = newNumberWithoutLetters.ToCharArray();
int j = newNumberWithoutLetters.Length;
if (!((documentNumber2[j - 1] == 47 || documentNumber2[j - 1] == 92) || (documentNumber2[j - 1] == 46 || documentNumber2[j - 1] == 44)) && cut)
newNumberWithoutSings = documentNumber2[j - 1] + newNumberWithoutSings;
newNumberWithoutSings = documentNumber2[j - 1] + newNumberWithoutSings;
if (howMuchCut == newNumberWithoutLetters.Length - length)
newNumber = newNumberWithoutSings;
if (newNumberWithoutSings.Length > length)
char[] documentNumber3 = new char[newNumberWithoutSings.Length];
documentNumber3 = newNumberWithoutSings.ToCharArray();
int k = newNumberWithoutSings.Length;
newCutNumber = documentNumber3[k - 1] + newCutNumber;
newNumber = newCutNumber;